Blackboards and chalks are being replaced by more modern whiteboards on which users can draw with felt tip pens so that the texts and drawings become read into a computer system. In digital form, the user input can also be easily stored and distributed. It is also possible to produce large touch displays on which the users can draw by their fingers or with some suited pens or styluses so that a computer forms drawings and texts as drawn by the user. Such touch screens can be thus used in a drawing mode in which new drawings can be made. It is also possible to show presentations on such touch screens in which case slides are shown on the display and changed to next or previous e.g. on touching the display. However, when many functions are provided by one element, the users need to be given suitable controls for selecting the desired operating mode. Such controls should be inexpensive, easy to learn, ergonomic and reliable.
An object of the present invention is to remove or mitigate the aforementioned problems or at least to provide one or more new technical alternatives for existing techniques.